1. Field of the Invention
The present invention relates to a method of adjusting two shielding elements, with the method including:
transporting a metal strip having a predetermined width, a central axis, and edge regions on a roller table having a roller table central axis with the metal strip having a temperature profile over the width of the metal strip;
shielding a cooling medium from the edge regions of the metal strip with shielding elements, and
adjusting the shielding elements so that the temperature profile behind the shielding elements, as seen in the transporting direction, is approximated to a nominal temperature profile.
The present invention also relates to an assembly including a roller table for transporting a metal strip having a predetermined width in a transporting direction, and shielding elements for shielding of a cooling medium from the edge regions of the metal strip.
2. Description of the Prior Art
Such an adjusting method and a roller table are disclosed, for example, in German document DE 32 30 866 C2.
Metal strips are cooled in order to achieve certain metallurgical properties. Since the edge regions of the metal strip, as a rule, are cooler than the central region of the strip, a cooling medium is shielded from the edge regions of the metal strip in the state-of-the-art. With such a procedure, a uniform temperature profile over the width of the strip can be achieved behind the cooling segments.
It is an object of the present invention to provide a method of adjusting two shielding elements and a roller table which permit to achieve an even more uniform temperature profile distribution in the metal strip.
This and other objects of the present invention, which will become apparent hereinafter, are achieved by adjusting the shielding elements asymmetrically with respect to the central axis of the roller table.
According to the present invention, the roller table is equipped with adjusting driving mechanisms, for adjusting the shielding elements asymmetrically with respect to the central axis of the roller table.
In accordance with the present invention, the corresponding deviations, especially a distance of the strip central axis from the central axis of the roller table, an asymmetry of the temperature profile over the width of the strip in front of the shielding elements, and an asymmetry of the temperature profile over the width of the strip behind the shielding elements are detected with appropriate sensor elements and are compensated for.
For the asymmetric adjusting of two shielding elements with respect to the central axis of the roller table, two adjusting driving mechanisms are required. The shielding elements can be adjusted mechanically either independently of one another each by its own adjusting driving mechanism or they can be adjusted together mechanically symmetrically by a first driving mechanism and mechanically asymmetrically by a second driving mechanism.
The adjusting method includes self-learning when:
the metal strip has a beginning,
before the start of the strip runs into the roller table, pre-adjustments are specified or present for the adjusting driving mechanisms by a control unit,
after the start of the tape runs into the roller table, the shielding elements are adjusted by the adjusting driving mechanisms to readjusted settings,
the readjusted settings are transmitted to the control unit, and
the control unit, based on the readjusted settings, modifies the previous pre-adjustments.
The construction of the assembly with a roller table is particularly simple if the shielding elements are disposed above the roller table, the shielding elements are constructed as longitudinal ducts extending in the transporting direction of the strip, and the cooling medium is supplied by the longitudinal ducts to transverse ducts extending transversely to the transporting direction.
If the transverse ducts are disposed between the adjusting driving mechanisms and the roller table, the adjusting elements are protected against heat and a possible rising of the metal strip.